It would be swell if tools/features could be added to make multi-body solid part files flexible.  I know part files are treated as completely rigid in assemblies right now, and you need a sub-assembly with multiple parts to create a flexible component, but what if there was a way to mark degrees of freedom for bodies internal to part model files and then set solid part files as flexible in assemblies? 

I can think of a few reasons to do this:

- when I model assemblies I prefer (if possible) to keep purchase items as single solid part files and not sub-assemblies.  It's quicker/easier to manage SW internal BOMs that way. 

- For anyone using a vault, it's less files you need to store in the vault. 

-For anyone not using a true vault (but just using a group folder for their commonly used purchase stuff), its still going to be less files you need to store.  More importantly it's less files you'll have to navigate through when you search a number, less image icons to sort through; less clutter.

- Items like hinges or prox sensors are single-line item purchase items used all the time in automation design - having to split bodies into separate parts or make sub-assemblies just to be able to rotate a hinge or position prox hex nuts is kind of tedious (ill download McMaster carr stuff and often find myself doing this).  Or how about cylinders?  The same cylinder could be used for an infinite different number of advance/retract motions without having to create configurations or job specific copies of the cylinder files.  Wouldn't it be nice to have just one single part file drop into an assembly and still have the freedom to work the way it does as a flexible sub-assembly? 

To be able to build pertinent movement into a single part file seems like it would very be handy.  Maybe there are reasons not to do this that I'm just overlooking though?

(I guess virtual files within sub-asms could sort of achieve this goal of 1-file-for-1-BOM-line item? but ive had issues running pack & go on asms with virtual files before.  Other than that, maybe you'd have issues quickly processing the part files this way within an assembly?)